From the past, there has been used a stapler for binding the binding sheets by means of a metal-made staple. In case of binding paper-sheets by using such a stapler by means of a metal-made staple, there sometimes happens a case in which it is requested to separate the paper-sheets and the staple when the paper-sheets are processed by a paper shredder or for the reason of recycling. Also, in view of the safety problem, it is not preferable to bind documents used in a work section handling food articles by means of a metal-made staple.
Also, differently from the above description, there has been proposed a stapler which binds binding sheets by means of a staple formed by a soft raw material of paper or the like (for example, see Japanese Patent Application Publication No. 2001-300865).
The stapler disclosed in the Japanese Patent Application publication No. 2001-300865 is one which binds binding sheets by means of a paper-made staple shaped in a shape in which both the edges thereof are bent in one direction beforehand. The stapler disclosed in the Japanese Patent Application publication No. 2001-300865 is one in which notch openings are formed in the binding sheets by a cutter, both the leg portions of the staple penetrate these notch openings and thereafter, both the leg portions are bent along a staple receiving table and are bonded together.